10
Consider the following example using a Jointmeter with a 25 mm range transducer.
R
0
= 3150 digits
R
1
= 6000 digits
T
0
= 15.3° C
T
1
= 20.8° C
G = 0.00356 mm/digit
K = ((6000
0.000369) + 0.572)
0.00356 = 0.0099
L
C
= 17.3
10
-6
259
(20.8 - 15.3) = 0.024
D =(6000 – 3150) x 0.00356 = 10.146 mm
D
corrected
= ((R
1
- R
0
)
C) + ((T
1
- T
0
)
K) + L
C
D
corrected
= ((6000 - 3150)
0.00356) + (20.8 - 15.3)
0.0099) + 0.024
D
corrected
= (2850
0.00356) + (5.5
0.0099) + 0.024
D
corrected
= 10.146 + 0.054 + 0.024
D
corrected
= +10.224 mm
As can be seen from the above example, the corrections for temperature change are very
small and can usually be ignored.
4.3. Environmental Factors
Since the purpose of the jointmeter installation is to monitor site conditions, factors which
may affect these conditions should always be observed and recorded. Seemingly minor
effects may have a real influence on the behavior of the structure being monitored and may
give an early indication of potential problems. Some of these factors include, but are not
limited to: blasting, rainfall, tidal levels, excavation and fill levels and sequences, traffic,
temperature and barometric changes, changes in personnel, nearby construction activities,
seasonal changes, etc.
